An IR camera includes a thermal radiation capturing arrangement for capturing thermal radiation of an imaged view in response to input control unit(s) receiving user inputs from a user of the IR camera; a processing unit arranged to process the thermal radiation data in order for the thermal radiation data to be displayed by an IR camera display as thermal images; and an IR camera display arranged to display thermal images to a user of the IR camera. The processing unit is further arranged to determine at least one temperature reference value representing the temperature of the surrounding environment of the imaged view; and calculate at least one output power value indicative of an amount of energy dissipated in a part of the imaged view by using the temperature value of the thermal radiation data corresponding to said part of the imaged view and the at least one determined temperature reference value.